The Mechanism of Resistance of Pseudomonas Aeruginosa toβ-lactam Antibiotics and Clinical Significance

To study the resistant mechanism and clinical significance of pseudomonas aeruginosa toβ- lactam antibiotics,the outer mem brane permeability rate of30 P.aeruginosa strains to5 β- lactam antibiotics was m easured and their production ofβ- lactamase and theβ- lactam ase genes they carried detected. Furthermore,the relationship between the perm eability,β- lactam ase and the clinical effects ofβ- lactam antibiotics was observed. By using 1 4C- penicillin and liquid- scintillant isotope assay,the affinity of penicillin binding proteins(PBPs) was m easured and their roles in the resistant m echanism studied.Itwas revealed thatthe perm eability rate was higher in sensitive strains than in resistantones(P<0 .0 5 ) .All strains harbored1- 4 β- lactamase genes and produced β- lactam ase.Higher permeability rate and higher degree of stability toβ- lactamase indicated better clinical therapeutic effects. The affinity of PBPs changed little without regard to the perm eability andβ- lactam ase. These results suggested that the permeability of outer mem brane andβ- lacta- mase,but not PBPs,played im portant roles in the resistant mechanism of P. aeruginosa toβ- lac- tam antibiotics and affected the clinical therapeutic effectiveness of som e patients.

A method of batch-purifying microalgae with multiple antibiotics at extremely high concentrations

Axenic microalgal strains are highly valued in diverse microalgal studies and applications. Antibiotics, alone or in combination, are often used to avoid bacterial contamination during microalgal isolation and culture. In our preliminary trials, we found that many microalgae ceased growing in antibiotics at extremely high concentrations but could resume growth quickly when returned to an antibiotics-free liquid medium and formed colonies when spread on a solid medium. We developed a simple and highly efficient method of obtaining axenic microalgal cultures based on this observation. First, microalgal strains of different species or strains were treated with a mixture of ampicillin, gentamycin sulfate, kanamycin, neomycin and streptomycin （each at a concentration of 600 mg/L） for 3 days; they were then transferred to antibiotics-free medium for 5 days; and finally they were spread on solid f/2 media to allow algal colonies to form. With this method, five strains ofNannochloropsis sp. （Eustigmatophyceae）, two strains of Cylindrotheca sp. （Bacillariophyceae）, two strains of Tetraselmis sp. （Chlorodendrophyceae） and one strain ofAmphikrikos sp. （Trebouxiophyceae） were purified successfully. The method shows promise for batch- purifying microalgal cultures.

In Situ Raman Monitoring of Trace Antibiotics in Different Harsh Water Environments

In situ surface-enhanced Raman scattering(SERS)is a widely used operando analytical technique,while facing numerous complex factors in applications under aqueous environment,such as low detection sensitivity,poor anti-interference capability,etc.,resulting in unreliable detectability.To address these issues,herein a new hydrophobic SERS strategy has been attempted.By comprehensively designing and researching a SERS-active structure of superhydrophobic ZnO/Ag nanowires,we demonstrate that hydrophobicity can not only draw analytes from water onto substrate,but also adjust"hottest spot"from the bottom of the nanowires to the top.As a result,the structure can simultaneously concentrate the dispersed molecules in water and the enhanced electric field in structure into a same zone,while perfecting its own anti-interference ability.The underwater in situ analytical enhancement factor of this platform is as high as 1.67×10^(11),and the operando limited of detection for metronidazole(MNZ)reaches to 10^(-9)M.Most importantly,we also successfully generalized this structure to various real in situ detection scenarios,including on-site detection of MNZ in corrosive urine,real-time warning of wrong dose of MNZ during intravenous therapy,in situ monitoring of MNZ in flowing wastewater with particulate interference,etc.,demonstrating the great application potential of this hydrophobic platform.This work realizes a synergistic promotion for in situ SERS performance under aqueous environment,and also provides a novel view for improving other in situ analytical techniques.

Prescription of Antibiotics in Oral-Dental Practice: Case of the Dental Practice at the Coyah Prefectoral Hospital in the Republic of Guinea 2019-2020

Introduction: Antibiotics are medications that have the property of destroying bacteria or preventing their proliferation. The aim of this study is to evaluate antibiotic prescriptions in oral practice: case of the dental office of the Coyah prefectural hospital. Methods: This is a descriptive cross-sectional study which took place from August 2019 to January 2020 inclusive, i.e. a duration of six (6) months, during which 400 patients were identified. Results: Our results revealed a frequency of 70% of antibiotic prescriptions. The 16 - 25-year-old age group was the most dismayed, at 47.25% and with an average age of 27.78 years. Men represent 55% compared to 45% of women, i.e. sex ratio of 1.22. Pulp gangrene was the most common pathology in 55% of cases. The most prescribed family was Betalactamine or 61.71% and the most represented molecules were Amoxicillin with 56.10% followed by Metronidazole or 34.16%. And the favorable prognosis was observed in 99% of cases. Conclusion: Prescription should always be based on the benefit-risk ratio. This prescription by practitioners aims to prevent or eradicate infections and pain in order to obtain a good therapeutic result.

Antibiotic Resistance Profile of Serotypes of Streptococcus pneumoniae Strains in Bangui, from 2017 to 2022: Case of Serotype 1

Goals: The aim of this study was to determine the antibiotic resistance profile of serotypes of Streptococcus pneumoniae strains circulating in Bangui. Methodology: A prospective and analytical analysis was carried out at the National Laboratory of Clinical Biology and Public Health from 2017 to 2022. The strains came from our study on the contribution to the study of antibiotic sensitivity of Streptococcus pneumoniae strains. The multiplex PCR test was used for its cost-effectiveness in terms of amplifiers which can be purified in order to be sequenced. It also makes it possible to detect several germs as well as their serotypes. For a PCR reaction, several elements are involved in the reaction medium or Master Mix. These are the desoxyribonucleotides (dNTPs), the magnesium ions (MgCl2) and the primers. A set of 14 primers divided into 3 classes were used. Class 1 primers served as an internal control by targeting the cpsA gene. It is a highly conserved gene found in capsular loci characterized to date. The primers of the second class were used to target specific serotypes by specific reactions (out of six possibilities). The group reaction was carried out using the primers of the third class in order to carry out an initial screening of the samples and to classify the pneumococcal isolates. Related serotypes were grouped based on the amplification of common genes. Using the technique of electrophoresis on agarose gel and an ultraviolet radiation device, the migration bands are then visualized and analyzed. The data collected had been entered into Excel 2010 and analyzed with Epi info 7. The exact Fischer chi2 test at the 5% threshold, the relative risk and its 95% confidence interval were used to compare the proportions and determine the associations. Results: 187 antibiotic-resistant strains of Streptococcus pneumoniae were collected. The average frequency of serotypes 1, 9A, 4 and untypeable identified were 43.59%, 18.18%, 18.27% and 39.57% respectively. The frequency of serotype 1 was predominant for the age group over five years old with 56.88%. The male sex was predominant with 55.08% for serotype 1. Resistance to penicillin and gentamicin for serotype 1 during this study, for the age group under 5 years old, was 77%. For serotypes 19A and 4, tetracycline resistance was predominant with 20% for the age group under 5 years. The resistance to penicillin and gentamicin of non-typeable serotypes was 33% for the age group under 5 years old. For the age group over 5 years old, resistance to erythromycin predominated at 37%. The distribution of serotypes by sex depending on antibiotic resistance was variable. There was a statistically significant association between identified serotypes and antibiotic resistance (p Conclusion: The study determined serotypes 1, serotypes 19A, serotypes 4 and non-typeable serotypes. These results would be due to the quality of vaccination or poor protection of vaccines.

Antimicrobial Activity of Some Commercial Toothpastes and Antibiotics on Two Oral Pathogenic Bacteria—An in-Vitro Study

Oral health problems such as periodontal diseases, dental caries, and endodontic infections have a significant negative impact on oral health and impose a substantial financial burden on the global population. The prevalence of these issues is increasing due to the buildup of bacterial plaque and the growing resistance of bacteria to antimicrobial treatments. The aims of this study to evaluate the anti-bacterial activity of four types of antibiotics (Amoxicillin, Augmentin, Azithromycin and Metronidazole) and four types of toothpastes (Sensodyne, ipana, denta and cariax Gingival Kin) on two oral pathogenic bacteria (Streptococcus mutans and Staphylococcus epidermidis). Bacterial samples of previously isolated Streptococcus mutans and Staphylococcusepidermidis were used as test organisms and the Kirby-Bauer disc diffusion method was employed to assess the antibacterial efficacy of various antibiotics and evaluate the impact of different toothpastes using a filter paper disc agar measurement technique. Each filter disc was saturated with toothpaste solution in a test tube for approximately 30 to 40 seconds, after which they were placed on Mueller-Hinton broth bacterial cultures in petri dishes. These Petri dishes were then incubated at 37°C for 24 hours, and the clear zone’s diameter (inhibition zone in mm) was subsequently measured and the results were recorded. The results demonstrated that Sensodyne toothpaste and Metronidazole antibiotic were ineffective against both types of bacteria, while Augmentin and Amoxicillin were effective by high diameter inhibition zones of growth against S. mutans and Azithromycine against S. epidermidis. Also Ipana, Denta, and Cariax Gingival Kin toothpastes exhibited a moderate effect against the two bacteria. This study suggests that certain antibiotics and toothpastes can effectively inhibit the growth of harmful oral bacteria, but not all of them are effective.

Simultaneous Degradation, Dehalogenation, and Detoxification of Halogenated Antibiotics by Carbon Dioxide Radical Anions

Despite the extensive application of advanced oxidation processes(AOPs)in water treatment,the efficiency of AOPs in eliminating various emerging contaminants such as halogenated antibiotics is constrained by a number of factors.Halogen moieties exhibit strong resistance to oxidative radicals,affecting the dehalogenation and detoxification efficiencies.To address these limitations of AOPs,advanced reduction processes(ARPs)have been proposed.Herein,a novel nucleophilic reductant—namely,the carbon dioxide radical anion(CO_(2)^(·-))—is introduced for the simultaneous degradation,dehalogenation,and detoxification of florfenicol(FF),a typical halogenated antibiotic.The results demonstrate that FF is completely eliminated by CO_(2)^(·-),with approximately 100%of Cland 46%of Freleased after 120 min of treatment.Simultaneous detoxification is observed,which exhibits a linear response to the release of free inorganic halogen ions(R^(2)=0.97,p<0.01).The formation of halogen-free products is the primary reason for the superior detoxification performance of this method,in comparison with conventional hydroxyl-radical-based AOPs.Products identification and density functional theory(DFT)calculations reveal the underlying dehalogenation mechanism,in which the chlorine moiety of FF is more susceptible than other moieties to nucleophilic attack by CO_(2)^(·-).Moreover,CO_(2)^(·-)-based ARPs exhibit superior dehalogenation efficiencies(>75%)in degrading a series of halogenated antibiotics,including chloramphenicol(CAP),thiamphenicol(THA),diclofenac(DLF),triclosan(TCS),and ciprofloxacin(CIP).The system shows high tolerance to the pH of the solution and the presence of natural water constituents,and demonstrates an excellent degradation performance in actual groundwater,indicating the strong application potential of CO_(2)^(·-)-based ARPs in real life.Overall,this study elucidates the feasibility of CO_(2)^(·-)for the simultaneous degradation,dehalogenation,and detoxification of halogenated antibiotics and provides a promising method for their regulation during water or wastewater treatment.

Single flow treatment degradation of antibiotics in water using falling-film dielectric barrier discharge

The environmental contamination caused by antibiotics is increasingly conspicuous due to their widespread manufacture and misuse. Plasma has been employed in recent years for the remediation of antibiotic pollution in the environment. In this work, a falling-film dielectric barrier discharge was used to degrade the antibiotic tetracycline(TC) in water. The reactor combined the gas-liquid discharge and active gas bubbling to improve the TC degradation performance. The discharge characteristics, chemical species’ concentration, and degradation rates at different parameters were systematically studied. Under the optimized conditions(working gas was pure oxygen, liquid flow rate was 100 mL/min, gas flow rate was 1 L/min,voltage was 20 kV, single treatment), TC was removed beyond 70% in a single flow treatment with an energy efficiency of 145 mg/(kW·h). The reactor design facilitated gas and liquid flow in the plasma area to produce more ozone in bubbles after a single flow under pure oxygen conditions, affording fast TC degradation. Furthermore, long-term stationary experiment indicated that long-lived active species can sustain the degradation of TC. Compared with other plasma treatment systems, this work offers a fast and efficient degradation method, showing significant potential in practical industrial applications.

A novel Ag/ZnO core-shell structure for efficient sterilization synergizing antibiotics and subsequently removing residuals

The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by increasing its bactericidal performance,the emergence of drug resistance is certainly delayed,so that there's not enough time for developing drug resistance during treatment.Therefore,we selected typical representative materials of metal Ag and semiconductor ZnO nano-bactericides to design and synthesize Ag/ZnO hollow core-shell structures(AZ for short).Antibiotics are grafted on the surface of AZ through rational modification to form a composite sterilization system.The research results show that the antibacterial efficiency of the composite system is significantly increased,from the sum(34.7%+22.8%-57.5%)of the antibacterial efficiency of AZ and gentamicin to 80.2%,net synergizes 22.7%,which fully reflects the effect of 1+1>2.Therefore,the dosage of antibiotics can be drastically reduced in this way,which makes both the possibility of bacterial resistance and medical expenses remarkably decrease.Subsequently,residual antibiotics can be degraded under simple illumination using AZ-self as a photocatalyst,which cuts off the path of environmental pollution.In short,such an innovative route has guiding significance for drug resistance.

Mobile genetic elements facilitate the transmission of antibiotic resistance genes in multidrug-resistant Enterobacteriaceae from duck farms

Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms in Zhejiang Province,China,were investigated.A total of 215 isolates were identified as Escherichia coli(64.65%),Klebsiella pneumoniae(12.09%),Proteus mirabilis(10.23%),Salmonella(8.84%),and Enterobacter cloacae(4.19%).Meanwhile,all isolates were resistant to at least two antibiotics.Most isolates carried tet(A)(85.12%),blaTEM(78.60%)and sul1(67.44%)resistance genes.Gene co-occurrence analysis showed that the resistance genes were associated with IS26 and integrons.A conjugative IncFII plasmid pSDM004 containing all the above MGEs was detected in Proteus mirabilis isolate SDM004.This isolate was resistant to 18 antibiotics and carried the blaNDM-5 gene.MGEs,especially plasmids,are the primary antibiotic resistance gene transmission route in duck farms.These findings provide a theoretical basis for the rational use of antibiotics in farms which are substantial for evaluating public health and food safety.

Indication of conservative treatment by antibiotics for uncomplicated and complicated acute appendicitis

BACKGROUND Acute appendicitis is one of the most common emergency abdominal disease,and recent studies have evaluated conservative treatment using antibiotics for uncomplicated appendicitis.Although the efficacy of conservative treatment for uncomplicated appendicitis is known,its efficacy for complicated appendicitis remains unknown,so are risk factors for the conservative treatment of appendi-citis.In our institution,conservative treatment has long been the first choice for most appendicitis cases,except for perforation.Therefore,this novel study inves-tigated the outcomes of conservative treatment for uncomplicated and compli-cated acute appendicitis and the risk factors associated with conservative treat-ment.treatment.The significant and independent predictors of resistance to conservative treatment were body temperature≥37.3℃,appendicolith and Douglas sinus fluid visible on computed tomography(CT).The rate of resistance to conservative treatment was 66.7%(6/9)for patients with the above three factors,22.9%(8/35)for patients with two factors(appendicolith and body temperature≥37.3℃),16.7%(2/12)for patients with two factors(Douglas sinus fluid and appendicolith)and 11.1%(1/9)for patients with two factors(Douglas sinus fluid and body temperature≥37.3℃).CONCLUSION A temperature≥37.3℃,appendicolith and Douglas sinus fluid on CT might be clinical risk factors of resistance to conservative treatment for acute appendicitis.

Early clinical outcomes of two regimens of prophylactic antibiotics in cardiac surgical patients with delayed sternal closure

BACKGROUND Delayed sternal closure(DSC)can be a lifesaving approach for certain patients who have undergone cardiac surgery.The value of the type of prophylactic antibiotics in DSC is still debatable.AIM To investigate clinical outcomes of different prophylactic antibiotic regimens in patients who had DSC after cardiac surgery.METHODS This was a retrospective observational single-center study.Fifty-three consecutive patients who underwent cardiac surgery and had an indication for DSC were included.Patients were subjected to two regimens of antibiotics:Narrow-spectrum and broad-spectrum regimens.RESULTS The main outcome measures were length of hospital and intensive care unit(ICU)stay,duration of mechanical ventilation,and mortality.Of the 53 patients,12(22.6%)received narrow-spectrum antibiotics,and 41(77.4%)received broad-spectrum antibiotics.The mean age was 59.0±12.1 years,without significant differences between the groups.The mean duration of antibiotic use was significantly longer in the broad-spectrum than the narrowspectrum group(11.9±8.7 vs 3.4±2.0 d,P<0.001).The median duration of open chest was 3.0(2.0-5.0)d for all patients,with no difference between groups(P=0.146).The median duration of mechanical ventilation was significantly longer in the broad-spectrum group[60.0(Δinterquartile range(IQR)170.0)h vs 50.0(ΔIQR 113.0)h,P=0.047].Similarly,the median length of stay for both ICU and hospital were significantly longer in the broadspectrum group[7.5(ΔIQR 10.0)d vs 5.0(ΔIQR 5.0)d,P=0.008]and[27.0(ΔIQR 30.0)d vs 19.0(ΔIQR 21.0)d,P=0.031].Five(9.8%)patients were readmitted to the ICU and 18(34.6%)patients died without a difference between groups.CONCLUSION Prophylactic broad-spectrum antibiotics did not improve clinical outcomes in patients with DSC post-cardiac surgery but was associated with longer ventilation duration,length of ICU and hospital stays vs narrow-spectrum antibiotics.

Current trends in nanomaterials-mediated biosensing platforms and signal amplification strategies for antibiotics detection in dairy products

Dairy products have become one of the most prevalent daily foods worldwide,but safety concerns are rising.In dairy farming,unscrupulous traders misuse antibiotics to treat some diseases such as mastitis in cows,leading to antibiotic residues in dairy products.Rapid,sensitive,and simple detection methods for antibiotic residues are particularly important for food safety in dairy products.Traditional detection technology can effectively detect antibiotics,but there are defects such as complicated pre-treatment and high cost.Biosensors are widely used in food safety due to fast detection speed,low detection cost,strong anti-interference ability,and suitability for the field application.Nevertheless,these sensors often fail to trigger the signal conversion output due to low target concentration.To cope with this issue,some high-efficiency signal amplification systems can be introduced to improve the detection sensitivity and linear range of biosensors.In this review,we focused on:(i)Sources and toxicity of major antibiotics in animal-derived foods.(ii)Nanomaterial-mediated biosensors for real-time detection of target antibiotics in animal-derived foods.(iii)Signal amplification techniques to increase the sensitivity of biosensors.Finally,future prospects and challenges in this research field are discussed.

The Role of Prophylactic Antibiotics for Percutaneous Procedures in Orthopaedic Surgery

Introduction This study investigates the current practice of surgeons in the United Kingdom with regards to their usage of prophylactic antibiotics for percutaneous orthopaedic procedures. Methods An electronic survey of 10 questions was devised and sent to all members of the British Orthopaedic Association. Three hundred and three replies were obtained (172 consultants, 131 trainees). Results Only half the numbers of orthopaedic surgeons would routinely use antibiotics for percutaneous K-wire fixation. Of the other half, 28% would never prescribe antibiotics and 22% would use them in special circumstances only. These ‘special circumstances’ were also not standardised. 92% of those who did prescribe antibiotics would administer single dose only and the majority (90%) would administer them during induction. There was no significant difference between trainees and consultants or between different orthopaedic procedures with regards to whether prophylactic antibiotics were prescribed or not. Discussion This survey highlights the split of opinion amongst practising orthopaedic surgeons as to the necessity or otherwise of antibiotic prophylaxis in percutaneous orthopaedic procedures. There are no reliable guidelines and further work should be carried out to investigate this subject.

Effect Found in the Combination of Kitasamycin with Other Antibiotics Used against <i>Actinobacillus pleuropneumoniae</i>

Background: Combinations of antibiotics are used to increase the therapeutic options via the simultaneous activities of two compounds. The goals of combination therapy are to resolve the bacterial infection while reducing the treatment cost. The use of kitasamycin is used frequently and in addition to other antibiotics, the desired combinations were not found. Methods: Fields strains: we use serotypes 1, 3, 5 y 7. Microbial culturing: The serotypes 1, 3, 5 y 7 was identified. Antibiotics and Reagents: The antibiotics used were kitasamycin;enrofloxacin and oxolinic acid. The following combinations were tested: a) kitasamycin with enrofloxacin;b) kitasamycin with norfloxacin;and c) kitasamycin with oxolinic acid. Preparation of bacterial suspensions: The cultures were adjusted to a concentration of 5 colony-forming units per ml (CFU/ml) using the same sterile culture medium as the diluent. Determination of the fractional inhibitory concentrations (FICs): To test each combination and their interactions and to calculate the fractional inhibitory concentration (FIC) of each antibiotic. Calculation of the index of the fractional minimum inhibitory concentration (FMIC): The FMIC index was calculated by applying the following formula: FIC index = FIC of antibiotic A/FIC of antibiotic B. Results: What was found showed that: A combination of kitasamycin and norfloxacin has been shown to have an indifferent effect. A combination of kitasamycin and enrofloxacin had antagonistic effects against all of the Actinobacillus pleuropneumoniae serotypes studied. Finally, a combination of kitasamycin and oxolinic acid had antagonist effects against serotypes 1, 3 and 5 and a synergistic effect against serotype 7. Conclusion: The “in vitro” combination Kitasamycin-Norfloxacin showed an indifferent effect, and combination Kitasamycin and Enrofloxacin demonstrated an antagonistic interaction between these two antibiotics. A combination of Kitasamycin and Oxolinic Acid had synergistic effect against serotype 7.

Resistance to Beta Lactam Antibiotics of <i>Pseudomonas aeruginosa</i>Isolated in Community Infections within HIV Infected Persons in Lomé-Togo

Objective: Describe resistance to beta lactam antibiotics of Pseudomonas aeruginosa in community infection within HIV-1 infected persons. Methods: We have studied prospectively from June 15th to December 31st 2013 inthe Clinic Hotel-Dieu and NGO VISA of Lomé, adult HIV-1 infected patients under anti retroviral therapy combining tenofovir, lamivudine and efavirenz for at least one year. The technique of agar diffusion susceptibility using discs of Ticarcillin + clavulanic acid is used to study the β-lactamase production. The diagnosis of species was performed by the chloroform test and the test for sensitivity to kanamycin and colistin. Results: Thirty five strains of Pseudomonas aeruginosa were obtained. The T-lymphocytes CD4 mediane was 575 cells/mm3 of blood. Urine represented 15 cases, skin abscesses 11 cases, externa suppurate otitis 7 cases and vaginal swab for 2 cases. The phenotypes were: wild phenotypes 23 cases (65.7%), resistant phenotypes 12 cases. Among resistant phenotypes, 4 were complex phenotype;5 were ESBL phenotypes;2 were hyper productive cephalosporinases phenotypes and 1 was a specific phenotype with impermeability to imipenem. Conclusion: The acquisition of resistance of Pseudomonas aeruginosa to beta lactam antibiotics in community infections among HIV-1 infected person incentives controls and promotes the rational use of antibiotics.

N-Acylhomoserine Lactones (AHLs), QseB/C Gene Detection, Virulence Factors and Antibiotics Resistance of <i>Aeromonas hydrophila</i>

The aim of this research was to detect the N-acyl homoserine lactones (AHLs) production and QseB/C gene of Aeromonas hydrophila. We analyzed the potentials of these isolates of Aeromonas hydrophila in causing biofilm formation, hemolysis, protease, and lipase. The antibiotic susceptibility of the 15 Aeromonas hydrophila isolates was also investigated. The detection of AHLs was carried out using the Chromobacterium violaceum strain CV026 as biosensors. The isolated strains were tested for the reaction of C. violaceum CV026 by cross-streaking on an agar plate. Production of AHLs was determined by the diffusing via the agar plates and the tinge of the biosensor strains. All isolated strains produced AHLs. A polymerase chain reaction (PCR) showed the isolated strains had qseB and qseC genes. Susceptibility tests of A. hydrophila isolates were administered against 25 different antibiotic disks representing 12 classes of antibiotics. The strains were highly resistant to β-Lactam with 96.7% showing resistibility, whereas 97.7% susceptibility was found towards Aminoglycoside class of the antibiotic used. 60% showed intermediate resistant to Polypeptide. 100% of the strains showed no resistant to Aminoglycoside, Polypeptide, Monobactam, and Carbapenems class of antibiotics. Each of the isolates was found to be associated with at least one virulent factor. Our results clearly demonstrated that there is a presence of QseB/C genes in A. hydrophila and also produces AHLs molecule and virulence factors. The investigated isolates showed the pathogenic potential of Aeromonas hydrophila which makes it a serious threat to public health.

Antibacterial Effect of Herba paederiae and Kalimeris indica (L.) Sch.-Bip Combined with Antibiotics

[ Objective] TO observe the in-vitro antibacterial activity of Herba paederiae and Kalimeds indica （ L. ） Sch.-Bip and their antibacterial effect when being used with commonly used antibiotics. [ Method ] Staphylococcus aureus CMCC29178 and Escherichia coli ATCC25922 reference strains were used for the determination of minimal inhibitory concentration （MIC） and fractional inhibitory concentration （FIC） index using the broth microdilution method. [ Result] The aqueous extracts of Herba paederiae and Kalimeris indica （ L. ） Sch. -Bip had certain antibacterial effects on Staphylococcus aureus and Eschedchia coli. Synergistic effects or additive effects at different degrees were observed when they were applied with the commonly used antibiotics. [ Conclusion] Water extraction can be widely used to primarily screen medicinal plants with antibacterial activity.

Influences of antibiotics on plantlet regeneration via organogenesis in loblolly pine (Pinus taeda L.)

Three antibiotics ampicillin, carbenicillin, and cefotaxime were evaluated for their effects on induction, growth, and differentiation of organogenic calli, as well as rooting of regenerated shoots of three loblolly pine (Pinus taeda L.) genotypes. Of the antibiotics administered, cefotaxime maximally increased the frequency of callus formation and growth rate of organogenic calli, carbenicillin maximally increased the frequency of shoot regeneration and the average number of adventitious shoots per piece of organogenic callus, ampicillin maximally decreased the rooting frequency of regenerated shoots and mean number of roots per regenerated shoot, in comparison with antibiotic-free media. Compared with the control, ampicillin minimally increased the frequency of callus formation, cefotaxime minimally increased the frequency of shoot regeneration, and carbenicillin mini-mally decreased the rooting frequency of regenerated shoots in three loblolly pine genotypes tested. All three antibiotics in-creased the frequencies of callus formation and shoot regeneration, and reduced the rooting frequency of regenerated shoots suggested that the establishment of an efficient Agrobacterium tumefaciens-mediated transformation protocol for stable integra-tion of foreign genes into loblolly pine need to select a suitable antibiotic. This investigation could be useful for optimizing genetic transformation of conifers.

Investigation of Pseudomonas aeruginosa Resistance Pattern against Antibiotics in Clinical Samples from Iranian Educational Hospital

Pseudomonas aeruginosa (P. aeroginosa) is one of the opportunistic pathogens, which is the main cause of prevalent hospital infections worldwide. The aim of this study was to determine the prevalence of antibiotic resistance pattern against P. aeroginosa from clinical samples in our population. This study was performed during March 2009 to September 2011. During this period 233 clinical isolated samples from hospital patients were examined. In these studies, different strains of P. aeroginosa were isolated from samples, then microbiologically tested. Bacterial susceptibility was performed by the disc-diffusion tests with Kirby Baur disc diffusion tests in Muller-Hinto environment. Our results showed maximum antibiotic resistance (99.5%) of P. aeruginosa against Trimetoprime Solfametoxasole and Ciprofloxacin (55.33%), Amikacin (61%), Imipenem (33%), which were identified as the most effective antibiotics in this study. In conclusion, indeed most Pseudomonas aeruginosa strains infections are treated as soon as possible due to their severe resistance against antibiotics. So, we have to apply an accurate antibiotic treatment discipline, according to the finding, based on antibiogram, in order to prevent its spread and also, monitoring and optimization of antimicrobial use should be considered carefully.